Worsted stretch fabric and process for manufacturing same



United States Patent Ofiice 3,127,658 Patented Apr. 7, 1964 3,127,658WORSTED STRETCH FABRIC AND PROCESS FOR MANUFACTURING SAME DavidGlilrsmann, Bronx, N.Y., assignor to Burlington Industries, 1110.,Greensboro, N.C., a corporation of Delaware No Drawing. Filed Feb. 15,1962, Ser. No. 173,373 8 Claims. (Cl. 28--72) The present inventionrelates to worsted stretch fabric and novel procedures for preparingsame.

Woven stretch fabrics are becoming increasingly important in theclothing industry, for example, as suiting material or in leisureapparel and sportswear. The principal object of the present invention isto provide certain unique improvements in the preparation of worstedstretch fabric. A more specific object is the provision of a process forpreparing 100% worsted stretch fabric. Other objects will also behereinafter apparent.

Broadly stated, the method for preparing a worsted stretch fabricaccording to the present invention comprises first preparing a worstedstretch yarn by plying or twisting together (a) one end of worsted yarnhaving a spun twist in the 8 direction and a yarn count and grade numberwithin limits hereinafter defined and (b) another end of worsted yarnhaving essentially the same amount of twist as the first end but in theopposite or Z direction and a yarn count and grade number as indicated,the ply twist being in either the S or 2 direction, depending upon thedesired resultant twist direction. The ply twist should also be keptwithin specific limits and is usually equal to, or substantially equalto, the twist in the yarns before plying.

The plying operation is carried out under carefully controlled tensionconditions, i.e. the yarn should be kept taut during the plying, thetension thereon normally falling within the range of 5 to grams, asmeasured, on a Model 2804 Sipp-Eastwood Corp. tensiometer, between thepoint where two or more pre-ply ends are stabilized in tension and thepoint where ends are delivered to the final ply twisting guides. twistin the worsted stretch yarn is stabilized by heat treatment, notablysaturated steam at 65 C. to 77 C., until the twist is stabilized.Usually, this steam treatment takes from 30 to 60 minutes.

The thus stabilized stretch yarn is then used as the filling yarn andoptionally as the warp yarn to weave a fabric of any desired pattern.During this weaving operation, the filling yarn and warp yarn are bothkept under tension and a careful balance of picks and ends per inch ismaintained as discussed hereinafter to give the desired product. Thewoven fabric is then subjected to appropriate finishing operations, e.g.scouring, in the completely relaxed state and under absolute temperaturecontrol.

The success of the invention is due, among other factors, to the use ofcarefully selected Wools having a grade number and yarn count and degreeof twist, both prior to and after plying, within the limits prescribedbelow. Another critical aspect of the invention is the feature ofreeding out in weaving, i.e. increasing the space between the warp endsin the loom reed so that when the fabric is woven and relax finished,the filling yarn is allowed to bulk and the warp ends will be drawn incloser together thus providing a stretch fabric that will elongate andcontract. Additionally, the fabric construction must be such that thesum of the average number of picks and warp ends per inch for anyparticular weave does not exceed a definite maximum. These features areall discussed in detail below.

Where the stretch yarn is used only as the filling yarn, the fabric willstretch only in the filling direction, i.e.

Thereafter, the

widthwise. If desired, the stretch worsted yarn of the invention mayalso be used for the warp, as indicated above, and in such event, thefabric will have stretch in both directions. However, it is preferredthat the stretch yarn be used only as the filling yarn with conventionalworsted yarn of substantially the same count and grade number as thewarp to give a 100% worsted fabric which only stretches widthwise. Thestretch can be controlled from 8 to 22% by adjusting construction andfinish. It will be recognized that the degree of stretch. can be variedas desired depending on the amount of reeding out, the type of weave,the yarn used and other finishing factors.

The invention permits the preparation of fabric constructions which varyrather substantially. However, as noted above, it is essential to have acertain balance between the number of picks and ends per inch and thisis effected by insuring that a predetermined maximum is not exceeded forthe sum of the average number of picks (filling threads per inch) andends (warp threads per inch) sley. This maximum will vary depending onthe yarn count and type of Weave but a definite value can be calculatedfor any specific circumstance and should not be exceeded if asatisfactory stretch fabric is to be obtained. This maximum, which mayalso be called the maximum average loom fabric construction, may bedetermined for any particular type of weave and yarn count by thefollowing formula:

wherein:

M is the maximum average loom fabric construction or maximum average ofthe sum of the picks and ends per inch;

x is the yards per pound determined by multiplying the equivalent countof the stretch filling yarn by 560 (worsted hank);

is the number of ends in a repeat of the pattern;

is the number of interlacings per end in the weave,

interlacings being defined as the number of intertwinings or crossingsthat one end of the weave makes with the filling in one repeat of thepattern; and

B is the percent warp contraction depending upon weave and picks perinch. This value is obtained by subtracting the length of the greigewoven material from the length of the dressed or beamed material. Inother words, if the greige material has a length of yards and the beamedor wound length of warp yarn on the loom beam is yards, the warpcontraction (B) is 10% or .10 in the above formula.

The manner in which the above formula is used to determine the value of(M) is shown below using for purposes of illustration a so-called 2x2weave (FIG- URE 2, page 730 of The Modern Textile Dicitionary, by GeorgeLinton). A weave of this type has four ends in a repeat of the patternand two interlacings per end in the pattern. Using as the filling, astretch worsted yarn having an equivalent worsted count of 30, themaximum sum of the average number of picks and ends per inch can becalculated as follows, the B value being 10% for this given fabric:

Thus, using warp and filling yarn of the type indicated for a 2 x 2weave, the sum of the average picks and ends (or sley) per inch shouldnot exceed a value of 155.2. This represents the maximum average loomfabric construction which will give a stretch fabric as contemplatedherein and any number of picksand ends per inch may be used providedtheir sum is below the calculated maxi- 1 times 2=155.2

mum. Thus, the minimum average loom fabric construction may be anyreasonable value which gives a usable fabric, usually not below 50% ofthe calculated value of the maximum loom fabric construction and willdepend in any particular case on the type of product desired.

The worsted, pre-ply yarn used for the present invention must have aUSDA wool grade number between 62 and 80. Thus, it has been found thatthe use of yarns having a grade outside this range will not give adesirable stretch product. Additionally, the pre-ply yarns which areutilized should have a worsted count between 40 and 80 in order to givethe desired result. Particularly preferred yarns are those having acount around 60 and a grade number in the area of 80. As will beappreciated by those skilled in the art, an end of this preferred typeof yarn would be referred to as 1/60s80"s wool.

As indicated heretofore, the success of the invention is also due to theuse of worsted yarn which has been twisted a critical amount both beforeand after plying. The actual amount of twist will vary to some extentdepending on the grade and count of the yarn as shown in the tablebelow. However, speaking in general terms, the degree of twist for eachyarn end before plying will fall within the range of to 26 turns perinch in either the S or Z direction. A lower number of turns within theindicated range of 15 to 26 should be utilized as the count of the yarnis lowered within the range of 40 to 80. Additionally, the permissiblevariation in twist diminishes as a yarn of lower count is used. Thus,for example, the yarn twist should be within the range of 15 to 19 for ayarn count of 40, whereas yarn having an 80 count may be twisted over awider range beginning at 17 and terminating at the upper limit of 26.The optimum for any particular situation can be readily determined usingthe following table which correlates the count, grade number, twistbefore plying (pre-ply twist) and ply twist for the yarns used herein:

TABLE Wool Grade Pre-Ply Twist Ply-Twist Count (Worsted count) (USDA)(turns per (turns per) inch) S or Z inch) S or Z 62s to 80s 15 to 19 15to 19 66s to 80's 15 to 20 15 to 20 64s to 80s 15 to 20 15 to 20 64/70to 80s 15 to 21 15 to 21 64/70120 80s 15 to 21 15 to 21 70s to 80s 15 to21 15 to 21 70s to 80's 16 to 21 16 to 21 70s to 80s 16 to 21 16 to 2170s to 80s 16 to 22 16 to 21 to 80's 16 to 22 16 to 21 70s to 80s 16 to22 16 to 21 70's to 80s 16 to 22 16 to 21 70's to 80s 16 to 22 16 to 2180's 16 to 22 16 to 22 80s 16 to 22 16 to 22 80s 17 to 23 16 to 22 80s17 to 23 16 to 22 80's 17 to 24 16 to 23 80s 17 to 25 17 to 24 80s 17 to25 17 to 25 80s 17 to 26 17 to 25 It will be seen from the foregoingtable that the operable range for the ply twist is about the same as therange for the pre-ply twist applied to the separate yarn ends. Thus, theply twist can be Varied from 15 to 25 turns per inch depending on theyarn count and grade number and it will be noted that, as the yarn countincreases numerically, the permissible variation in the ply twistincreases from a minimum of four turns at yarn count 40-41 to a maximumof eight turns at yarn count 80.

As will be apparent from the foregoing, the stretch worted yarn used asthe filling yarn herein, and possibly also as the warp yarn, is preparedby plying one end of worsted yarn having a grade number, count and S orZ twist within the indicated ranges to a second end of worsted yarnwhich also has a grade number, count and spun twist within the limitsindicated except that the twist in the second end is opposed to thetwist in the first. Preferably, both yarns are identical in count andgrade number and also have the same degree of spun twist. The ply twistapplied to these two yarns may be either 8 or 2 as desired and should bewithin the ranges indicated in the foregoing table. A tension of 5 to 15grams should be kept on the yarns as they are being plied, as mentionedheretofore. The resulting plied or stretch worsted yarn should then bestabilized by means of steam (65 to 77 C., for 30 to 60 miutes) asdiscussed above. The thus stabilized product is then ready for use asthe filling yarn and, if desired, the warp yarn in weaving a Worstedstretch fabric according to the invention.

Apart from the reeding out feature referred to above and the indicatedlimit in the total number of picks and ends, the fabric of the presentinvention may be woven using generally standard techniques andapparatus. After the weaving operation, however, it is essential thatthe resulting greige worsted fabric be finished, e.g. scoured, underconditions providing for complete fabric relaxation and absolute thermalcontrol in each phase of the finishing operation. By thermal control, itis intended to mean that specific temperatures are applied for eachphase of the finishing process.

In the usual case, the following finishing operations are carried out inthe order indicated, the terminology utilized being standard in thetrade as shown, for example, in The Modern Textile Dictionary by GeorgeLinton:

(1) Batching, i.e. putting together different quantities of wovenmaterial which are to be processed together.

(2) Singe, the woven fabric being passed over a series of gas jets orhot plates to remove protruding fibers.

(3) Birch crab under controlled temperature. This involves running thecloth into a series of hot water baths or bowls of increasingly highertemperature with cooling in the final water bath or bowl. The purpose ofthis operation is to set the yarns in the material and to preventordinary shrinkage. In the case of a seven bowl Birch crab, the speed ofthe fabric is preferably about 30 yards per minute and usually withinthe range of 25 to 35 yards per minute depending on the type of fabric.Typical operating temperatures for the seven bowl Birch crab are thefollowing:

(4)Tack. This is a standard type of operation for the purpose ofprotecting the material against damage in subsequent wet-finishingoperations, e.g. scouring, etc.

(5) Scour. This may be done, for example, on a Dolly or full widthwasher using a high liquid level with no pressure or dragging on thematerial being scoured. The scouring agent should be non-alkaline, e.g.neutral or slightly acidic. Typically suitable scouring agents are theneutral nonionic detergents such as Adran C. Usual- 1v the scouring iscarried out at 4060 C. for from 25 to 45 minutes, preferably about 50 C.for 30 minutes, followed by rinsing with water at a lower temperature inthe range of 40-45 C., for about the same length of time. The use of anon-alkaline scouring agent with the fabric in a loose, relaxedcondition during scouring represents another finishing step which ispeculiar to the success of the present invention. This operation as wellas the other phases of finishing, permit dimensional shrinkage withoutexcessive structural shrinkage thus insuring a fabric of optimum stretchand recovery properties.

(6) De-tack.

(7) After de-tacking, the cloth is dry relaxed with about 10% overfeed.The purpose of the overfeed is to avoid any possible tension on thecloth thus insuring complete relaxation. The operation is carried out at105 to 115 C., preferably 110 C., at a fabric speed of 2025 yards perminute until the fabric is dry. This drying operation is carried out atlower temperatures and slower speeds than used for conventional fabricsin view of the necessity of overfeeding to keep the fabric in therelaxed state.

(8) Screen. This operation involves a visual examination of the fabricto ascertain if the preceding processes met quality standards and torepair if necessary torn selvages, seams, etc., that might be moreseriously damaged in subsequent operations.

(9) The fabric is then top steamed on an open steam table while in thecompletely relaxed state. Top steaming involves a treatment whereby thefabric is allowed to pass over an open steam table at *1015 yards/minuteat a saturated steam temperature of 100 C.

(10) The fabric is again tacked, dyed as desired under completelyrelaxed conditions and then de-tacked.

(11) Following the second de-tacking operation, the fabric is dryrelaxed with overfeed as before, screened and sheared.

(12) The sheared fabric is then again subjected to top steam on an opensteam table in the completely relaxed state. For some fabrics, aYorkshire crabbing may be desirable at this stage. In any case, the nextstep is cold water shrinkage. In the latter operation, the fabric isimmersed in a bath of cold water containing a wetting agent, at, forexample, 32 C. This treatment is one of the final shrinkage steps.

13) The finishing operation is continued by loop drying which ischaracterized by drying with warm air without tension at 115-125 C.,preferably 123 C., at 2025 yards/minute, preferably 20 yards per minute.The fabric is usually subjected to the above drying temperatures forapproximately five minutes.

14) The cold water shrinkage operation and loop drying proceduresmentioned above are repeated.

(15) The final operation is semi-decating which consists of winding thefabric between a hard leader blanket on a perforated cylinder, steamingat, for example, 100 C., for five minutes and steam exhaustion for fiveminutes which serves to set the material and improve its appearance.

Some fabrics require full-decating in lieu of semidecating. The formermay be accomplished by autoclave pressure steaming at 10 psi. for 3minutes followed by 8 minutes cooling.

Most, if not all, of the above-noted finishing steps are known, in andof themselves, in the worsted fabric art. However, it is acharacteristic requirement of the present process that the essentialfinishing operations, and notably those involving a liquid or dryingtreatment must be carried out with the fabric in a completely relaxedstate and in sequences, temperatures and time cycles as described above.

The invention is illustrated, but not limited, by the followingexamples:

Example 1 An end of 60s count worsted yarn having a USDA wool gradenumber of 80 (i.e. 1/60s 80s wool yarn) and a spun twist of turns perinch in the 2 direction was plied with an identical 1/60s 80s worstedyarn having a spun twist of 20 turns per inch in the 8 direction. Theply twist amounted to 20 turns in the 2 direction. The plying operationwas carried out with the two ends under tension (5 to 15 grams asmentioned heretofore).

The plied product was then stabilized by treatment with steam(saturated) at 75 C. for 60 minutes. The resulting worsted stretch yarnwas then ready to use in the preparation of a worsted stretch fabric.

A fabric was then woven with stretch yarn prepared as above as thefilling yarn in a 2 x 2 weave. The warp yarn was (two-ply) 2/60s 80'sworsted yarn consisting of two pre-ply single ends of 1/60 80s wool yarnwith a M- W times The fabric was woven with the warp yarns reeded outsufliciently to permit the filling yarn to bulk when the fabric wasrelax finished. This caused the fabric to narrow approximately 24.4% inwidth when finished. This means that the fabric when taut would stretchout a substantially equivalent amount from the relaxed state. Thereeding out used in this example meant that the warp ends were spacedfrom 8 to 10% farther apart than in a similar non-stretch type offabric. The reeding out also helped maintain the total number of picksand ends per inch below the maximum calculated value of 153 necessary toobtain optimum results.

After the weaving operation, the greige fabric was taken from the loomand finished as follows: batched with additional fabric made in the sameway, flame singed, subjected to the Birch crab, tacked and scoured onthe Dolly washer as mentioned heretofore. The fabric was then detacked,dry relaxed with overfeed, screened, top steamed on an open steam tablein the completely relaxed state, again tacked, dyed, detacked, again dryrelaxed with overfeed, screened, sheared and again subjected to topsteaming in the completely relaxed state. Following this treatment, thefabric was subjected to cold water shrinkage, then loop dried, coldwater shrinkage and loop dried again and semi-decated, all as heretoforedescribed.

The thus finished fabric comprised a highly attractive 100% Worstedfabric possessing inherent stretch characteristics in the fillingdirection. Clothing made from this fabric is characterized by comfortand stability. The fabric returns to its original shape after beingstretched and demonstrates no adverse changes after tailoring, wearingand repeated dry cleaning.

Example 2 Example 1 was repeated except that the warp yarn was replacedby the same stretch yarn as used in the filling. The resulting producthad stretch in the warp direction as well as in the filling direction.Otherwise, the stretch and other properties of the fabric wereessentially the same as the product of Example 1.

It will be appreciated that various modifications may be made in theinvention described herein without deviating from the scope thereof asset forth in the appended claims wherein:

I claim:

1. The method of preparing a worsted stretch fabric which comprisesproviding an end of worsted yarn having a yarn count within the range of40 to 80, a USDA wool grade number between 62 and and a spun twist inthe 8 direction of between 15 and 26 turns per inch, providing anotherend of worsted yarn having essentially the same yarn count, grade numberand spun twist in the Z direction, twisting said two ends together byapplying a ply twist in either the S or Z direction within the range of15 and 25 turns per inch, stabilizing the twist in said yarn, thereafterweaving a fabric using said plied yarn at least as the filling yarn, thewarp yarn being reeded out so that said filling yarn is provided spaceto bulk when the resulting fabric is finished.

2. The method of claim 1 wherein said fabric is finished in thecompletely relaxed condition.

M= times2 wherein:

M is the maximum sum of the average of the picks and ends per inch;

x is the yards per pound determined by multiplying the equivalent countof the filling yarn by 560;

y is the number of ends in a repeat of the pattern;

n is the the number of interlacings per end in the weave;

and

B is the percent warp contraction depending on the weave and picks perinch.

7. The method of preparing a stretch fabric which comprises providing anend of worsted yarn having an appropriate yarn count and grade numberand a spun twist in the 8 direction, providing another end of worstedyarn having essentially the same yarn count, grade number and spun twistin the 2 direction, twisting said two ends together by applying a plytwist in either the S or Z direction substantially equal to the originalnumber of turns in said ends before plying, thereafter weaving 8 afabric using said plied yarn as the filling yarn with the warp yarnbeing reeded out so that said filling yarn is provided space to bulkwhen the resulting fabric is relaxed and thereafter finishing saidfabric in the completely relaxed condition, the sum of the average picksand ends per inch of the woven fabric being not greater than M is themaximum sum of the average of the picks and ends per inch;

x is the yards per pound determined by multiplying the equivalent countof the filling yarn by 560;

y is the number of ends in a repeat of the pattern;

12 is the number of iuterlacings per end in the weave;

and

B is the percent warp contraction depending on the weave and picks perinch.

8. The stretch worsted fabric prepared by the method of claim 1.

References Cited in the file of this patent UNITED STATES PATENTS2,153,964 Lejeune Apr. 11, 1939 2,177,586 Voegeli Oct. 24, 19392,330,645 Voegeli Sept. 28, 1943 2,574,029 Foster Nov. 6, 1951 FOREIGNPATENTS 482,302 Great Britain a Mar. 28, 1938 UNITED STATES PATENTOFFICE CERTIFICATE OF CORRECTION Patent No 3,127 ,658 April 7 1964 DavidGliksmann It is hereby certified that error appears in the abovenumbered patent requiring correction and that the said Letters Patentshould read as corrected below.

Column 3, in the table, second column, opposite "42-43",

for "66's to 80's" read 64's to 80's column 3, line 70, for "worted"read worsted column 4, line 10, for "miutes" read minutes Signed andsealed this- 20th day of October 1964.

SEAL A IteSt: J

ERNEST W. SWIDER Y EDWARD J. BRENNER Attestin-g Officer Commissioner ofPatents

7. THE METHOD OF PREPARING A STRETCH FABRIC WHICH COMPRISES PROVIDING ANEND OF WORSTED YARN HAVING AN APPROPRIATE YARN COUNT AND GRADE NUMBERAND A SPUN TWIST IN THE S DIRECTION, PROVIDING ANOTHER END OF WORSTEDYARN HAVING ESSENTIALLY THE SAME YARN COUNT, GRADE NUMBER AND SPUN TWISTIN THE Z DIRECTION, TWISTING SAID TWO ENDS TOGETHER BY APPLYING A PLYTWIST IN EITHER THE S OR Z DIRECTION SUBSTANTIALLY EQUAL TO THE ORIGINALNUMBER OF TURNS IN SAID ENDS BEFORE PLYING, THEREAFTER WEAVING A FABRICUSING SAID PLIED YARN AS THE FILLING YARN WITH THE WARP YARN BEINGREEDED OUT SO THAT SAID FILLING YARN IS PROVIDED SPACE TO BULK WHEN THERESULTING FABRIC IS RELAXED AND THEREAFTER FINISHING SAID FABRIC IN THECOMPLETELY RELAXED CONDITION, THE SUM OF THE AVERAGE PICKS AND ENDS PERINCH OF THE WOVEN FABRIC BEING NOT GREATER THANM=(((X**1/2)(Y)(1-B))/(Y+N)) X 2 WHEREIN: